Radical scavenging capacity of methanolic Phillyrea latifolia L. extract: anthocyanin and phenolic acids composition of fruits

Abstract

Radical scavenging capacity of a crude methanolic extract from the fruits of Phillyrea latifolia L., commonly known as green olive tree or mock privet, was investigated with reference to anthocyanin standards, as flavonoids, and phenolic acid standards, as phenylpropanoids. Characterization with high performance liquid chromatography-diode array detection (HPLC-DAD) indicated the presence of keracyanin, kuromanin, cyanidin, ferulic acid, caffeic acid and rosmarinic acid at amounts of 289.1, 90.4, 191.4, 225.2, 221.2 and 190.1 mg/100 g fresh weight (FW) of fruits, respectively. Chlorogenic and p-coumaric acids were found to exist in lower amounts. Trolox equivalent antioxidant capacity (TEAC) and IC(50) values of the plant extract were found to be 1.8 mM Trolox equivalents (TE)/g FW of fruits and 69.4 µg/mL, respectively, indicating the close radical scavenging activity of the extract to those of keracyanin and p-coumaric acid. The crude methanolic P. latifolia L. fruit extract was seen to be fairly potent in radical scavenging. Total phenolic content (TPC) of the plant extract was found to be 1652.9 mg gallic acid equivalent (GAE)/100 g FW of fruits.

Figure 1

Chemical structures of (a) anthocyanins and (b) phenolic acids identified in P. latifolia L. fruits.

Figure 2

HPLC-DAD signals of (a) a crude methanolic extract from P. latifolia L. fruits for identification of its anthocyanin components, and (b) a standard anthocyanin mixture containing keracyanin, kuromanin and cyanidin obtained at 520 nm.

Figure 3

HPLC-DAD signals of (a) the acid-hydrolyzed methanolic extract from P. latifolia L. fruits obtained at 280 nm and (b) 330 nm, and (c) a standard mixture of phenolic compounds obtained at 330 nm and (d) the same standard mixture in (c) obtained at 330 nm after subjection to acid-hydrolysis.